How do I install BG2 to my desktop when it's broken up like it is. Really confused. It asks to be put where the installation folder is but there isn't one. Can anyone help me?

You should have an install file (.exe) and one or more .bin files. Make sure they're all in the same folder (doesn't matter where, as long as they're all in the same place). DO NOT unpack them. Leave them as they are, and run the install file.

*edit* Checking my backup file, it looks like there are three files:

setup_baldurs_gate_2
setup_baldurs_gate_2-1
setup_baldurs_gate_2-2

Make sure all three are in the same location and then double click the bolded one (setup_baldurs_gate_2).

Sorry but I don't see an install file.

Do you have the three files I noted in my edit of the previous post? If so, the one I bolded is the .exe install file.

First of all, how do you download it, just from webpage? Then the files are moved to your browsers download directory just look for it and doubleclick.
GoG Downloader: Install files are moved to the directory you specified in downloader, just look for it and doubleclick.
GoG Galaxy: will install automatically

Are you trying to download it through Galaxy or through the browser? Assuming you're doing so through browser, there should be three files; one .exe and two .bin (see image below). All three need to be in the same folder and, then, you need to run the .exe file and the game should start the installation process.

Good point. I DL through the DLer, so I forget about the Galaxy option.

So just put the three files in a folder marked installation and it should work?

No. Make sure that all of them are in the same folder (any folder), run the .exe file and it should start the installation process.

If the files are already in the same directory, simply double click the .exe file to launch the installation process.

Doesn't have to be marked 'installation'. It could be called anything. As long as the three files are in the same folder, it should install (you can specifiy where you want it to install when it starts the installation process, if you choose Options in the lower part of the install wizard window.

The only reason I want to put it on my desktop is so I can make it one game with BG1.

What? You can't take two different games and make them into one just by moving files around.

Not sure what you mean. Are you saying you want to use either the BGTrilogy mod or the wiedu mod to make it all a single game? If so, I don't think it needs to be installed on the desktop. It didn't for me, anyway.

Sounds like it would just be easier to use GOG Galaxy then transfer my main character to BG2 when I finish BG1.